Conflict ... I need more conflict!

I'm developing a contemporary romance around a woman whose inherited a large home from her late Grandmother. Unbeknown to her, her Grandmother allowed a local builder to rent out out a room in exchange for handy man expertise.

The heroine has decided to sell the home (without having viewed it) and has decided to take the pictures that will be shown in the ad for sale. Shes a freelance photographer. Like the Hero who is currently living in the house, on first sight the Heroine falls in love with the home. She allows the hero a few weeks to find another place before she moves in permanently, having decided to set down roots finally.

While investigating the house she finds evidence that her Grandmother once had a love affair with a younger man when she was in her twenties. Because all of the Heroine's family is now dead she decides to start looking for the members of a family she never knew she had.

I think this storyline is ok and will be fine, but I'm unsure if I have enough conflict between the Hero and Heroine to keep them apart for most of the book.

The handyman is recovering from having his no-good long-term girlfriend go off with his brother and has sworn he'll never let a woman get to him again... and he comes from a really rich and cultured family but he doesn't want anything to do with his family now--brother was the darling of the family etc etc

Don't overlook the potential of internal conflict. Both of these people may be commitment-phobic for their own reasons, or one of them could be clinging to feelings for someone no longer in the picture - the possibilities are endless.

I'd like to know more about the two characters. Perhaps the heroine's got a fiery temper, whereas the hero is more laid back. That's just an example, a slightly cliched example at that. But maybe clashing in their personalities are what lead to arguments and conflict.

Thanks guys, all your suggestions have given me alot to think over. I did a brainstorm session with a fellow writer of mine and we came up with a few ideas. One of which was the fact that the Heroine (Guinevere) doesn't trust men as she was cheated on by her ex-fiance.

The theme of the story I think is going to be cheating as the Grandmother did it when she was younger, and I believe I'm having the Hero (Rhys) be separated from his wife when the story begins. He's already decided that the marriage is over, but has yet to take action. Guinevere is the push he needs. I don't think he'll tell her in the beginning because they are strangers and it's none of her business. But as the book continues he finds it harder and harder to tell her.

That is plenty of conflict for a good story.
But, like cogito said, (jesus, we say that too much around here XD )
don't underestimate the powers of internal conflict. These often make much more interesting stories than external conflictsm particularly when the two are mixed properly.